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Using Preout connectivity for another Amplifier / SubWoofer

Wharfedale Speakers

sid_lochan

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Oct 16, 2008
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Hi all,

I want to use my existing SW (from HTiB Philips 4750) with my Yamaha 863.

I'm thinking about 2 ways to do so -

1. I take the SW-preout from Yamaha and feed it to MP3 direct or Digital port on Philips and then use the audio controls on Philips.

2. I feed the preout to SW direct.

Now my questions are -

1. Can HTiB sense the input coming from Yamaha?
2. Will the HTiB will decode the line in and route it to SW?
3. Is there any power mismatch could happen like preout power is too low or too high for the HTiB?

The SW is getting a single cable (15pin cable) from HTiB box and then all speakers are connected to it. But it is not clear that which cable pin is carrying LFE for SW. SW is 285 Watts RMS and active one. Frequency response- 30-20K.

Looking for your suggestions and ideas.

Enjoy!
Sid
 

marsilians

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Use the SW pre-out in the yamaha for what its meant for as it sends only certain freq range of signals. So connection shoudl be

Yamaha AVR (sw pre-out) - sub

Your sub may sound boomy if it does not have controls on it.


Now I am not sure what you mean by the sub having connections for the other speakers? It should be the central unit (amp) that should have the connections isn't it?




Hi all,

I want to use my existing SW (from HTiB Philips 4750) with my Yamaha 863.

I'm thinking about 2 ways to do so -

1. I take the SW-preout from Yamaha and feed it to MP3 direct or Digital port on Philips and then use the audio controls on Philips.

2. I feed the preout to SW direct.

Now my questions are -

1. Can HTiB sense the input coming from Yamaha?
2. Will the HTiB will decode the line in and route it to SW?
3. Is there any power mismatch could happen like preout power is too low or too high for the HTiB?

The SW is getting a single cable (15pin cable) from HTiB box and then all speakers are connected to it. But it is not clear that which cable pin is carrying LFE for SW. SW is 285 Watts RMS and active one. Frequency response- 30-20K.

Looking for your suggestions and ideas.

Enjoy!
Sid
 

venkatcr

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Jul 1, 2008
Messages
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Location
Chennai
I want to use my existing SW (from HTiB Philips 4750) with my Yamaha 863.

I'm thinking about 2 ways to do so -

1. I take the SW-preout from Yamaha and feed it to MP3 direct or Digital port on Philips and then use the audio controls on Philips.
2. I feed the preout to SW direct.

The concepts of 863 and your Philips HTIB are slightly different. In the 863, there are 8 independent signals sent - 7 for speakers and 1 for Sub or what is called the LFE channel.

In the Philips HTIB, ALL the signals are bundled together and sent to the sub. The sub in turn has connectors for the other speakers. That is why in the Philips, the cable from the main unit to the sub carries 15 pins. The sub does the separation of the signals (maybe amplifies them also) and sends them to the respective speakers.

In the 863, the pre out is an analog signal for each channel and a LFE output for two subs. Though there is a digital out, if you use this, you will be completely bypassing the capabilities of the 863 and using your Philips for all decoding and amplification.

Generally an AVR has 2 parts - a pre amplifier, and a power amplifier. The pre amplifier does all the decoding, DAC conversion etc, and the power amplifier increases the amplitude and power the speakers. Unless you use the Philips as a external amplifier, there is not much value in connecting the two.

The Digital (Coaxial) out in 863 is used for recorders, and this will have a very low voltage - in the order of 200 mV. Please check with your Philips specs whether this is enough for it to process. In optical out there is no voltage involved, but most AVRs do NOT have Optical out.

Now my questions are -

1. Can HTiB sense the input coming from Yamaha?

If your Philips has 8 analog inputs sockets (RCA) for each channel, yes it can sense the output coming from the 863.

2. Will the HTiB will decode the line in and route it to SW?

By this I am assuming you are referring to the Digital Out of the 863. Yes it may very well do that, but why use the 863 at all then? The 863 has much better decoding capabilities, and ideally you should connect either speakers to it or a external amplifier. As I said before, a digital signal is unprocessed. For all practical purposes, you can connect your DVD Player or other sources directly to the Philips, and bypass the 863.

3. Is there any power mismatch could happen like preout power is too low or too high for the HTiB?

If you are talking about analog pre out from the Yamaha to the analog input of the Philips, there will be no issues. Generally these follow internationally accepted voltages for such transfer.

The SW is getting a single cable (15pin cable) from HTiB box and then all speakers are connected to it. But it is not clear that which cable pin is carrying LFE for SW. SW is 285 Watts RMS and active one. Frequency response- 30-20K.

As I mentioned before, your cable to the sub is taking signal for all the speakers, and this cannot be separated. In most probability your main unit will have no amplification, and that is done inside the sub. Or the cable could be carrying 5 amplified signals and one KFE signal for the sub.

If you look at the 863 it will have a RCA out for the sub. This carries just the LFE signal, and none of the other signals.

If you want to connect the 863 and the Philips, it can only be done through the main unit, if at all.

Please read pages 17 to 24 of the 863 manual where the connections types and usages are explained.

Cheers
 
Last edited:

sid_lochan

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2. Will the HTiB will decode the line in and route it to SW?

By this I am assuming you are referring to the Digital Out of the 863. Yes it may very well do that, but why use the 863 at all then?

Cheers

Thanks Venkat & Marsillians for your valuable inputs.

Venkat, I want to send only SW preout to Philips as right now I'm not planning to buy one.

AS you have suggested that connectivity can be done only by main box, So my question is that will philips send the input to all speakers or only to SW.

My planned connectivity is - DVD/PS3-863-Spkrs-SWPreout-Philips digital in -SW. I'm using only L+R speakers.

Enjoy!
Sid
 

venkatcr

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AS you have suggested that connectivity can be done only by main box, So my question is that will philips send the input to all speakers or only to SW.

My planned connectivity is - DVD/PS3-863-Spkrs-SWPreout-Philips digital in -SW. I'm using only L+R speakers.

Let me get this straight.

Connection 1 - DVD Player/PS3 to 863
Connection 2 - 863 to Front L&R
Connection 3 - 863 sub out to Philips Digital In
Connection 4 - Philips to sub

If my understanding is correct, you are sending only the LFE channel to Philips, and that will power only the sub. BUT, and this is IMPORTANT. You CANNOT take the sub pre out from the 863 and connect it to the Philips Digital In. Sub Out from AVRs are not digital bot analog singals. Please don't even try this way of connecting. Only Analog outs must go to analogs in and only digital ins to digital outs. Some of these connectors look the same, so be careful and don't get confused.

If you take the Digital Coaxial Digital Out from the 863 and feed it to the Digital In of the Philips you will be sending signals for all the channels.

Cheers
 

hemantwaghe

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I've just downloaded the manual and some "mysteries" findings

1) Tortal power -1000 W PMPO - no mention of RMS

2) Sub power 250 W Pmpo

I feel that
1) Audio processing is done in player and then it is sent in sub
2) Sub might be too underpowered to give any good bass
3) No 6 channel input
4) You need to seprate subwoofer input from those 15 pins - you need a compatible connector - which are proprietry.
 

sid_lochan

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Let me get this straight.

If my understanding is correct, you are sending only the LFE channel to Philips, and that will power only the sub. BUT, and this is IMPORTANT. You CANNOT take the sub pre out from the 863 and connect it to the Philips Digital In.
Cheers

Thanks Venkat,

I'm not going to put LFE analog pre-out to digital input on Philips :). Now this HTiB does not have 7.1 input so only option is -
to use the L+R input on box and supply the LFE to that as it's also analog input. But then it will send the signal to all Speakers.

From Manual - Input sensitivity for Aux1 (Analog) is 1000mV.

I think I should buy a new SW :rolleyes: in next 2-3 months!


[/QUOTE]
1) Tortal power -1000 W PMPO - no mention of RMS

2) Sub power 250 W Pmpo
[/QUOTE]

Hemant,

It's 1000 watt/12000 watts PMPO. While on box its 1000 watt RMS.

Once I've changed the Box-SW 15 cable with a normal 15 pin VGA cable and it worked perfectly, the only thing is to figure out that which pin is carrying signals for which speaker.


Enjoy!
Sid
 

venkatcr

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Sid, if you can confirm that the sub does not amplify the other channels, why don't you just rewire the sub, and connect all speakers directly to the 863? A good electronics engineer should be able to do this in half a day. Will save you a bundle.

Cheers
 

sid_lochan

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Venkat,

Its quite hard to find a good engineer as well as enough spare time to spend on it in Delhi :D
I do get time to do R&d and other things but only after 9 PM so it seems that I've to do all the re-wiring.

The speakers of Philips 4750 are of different Ohms - CS - 2 Ohms and others are 4 Ohms.

Not sure how 863 will drive these speakers specially center speaker.

I've decided to use 863 for 2 channel music for next 1-2 months. Will upgrade to 7.1 by then :)

For movie viewing will go with Philips ;).

Thanks for you inputs and suggestions.

Enjoy!
Sid
 
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